[FFmpeg-devel] [PATCH] Change default behaviour of scale filter from 'progressive' to 'auto'

Michael Niedermayer michaelni at gmx.at
Mon Apr 2 11:42:46 CEST 2012

On Sat, Mar 31, 2012 at 07:52:13AM +0200, Michael Niedermayer wrote:
> On Sat, Mar 31, 2012 at 12:40:02AM +0000, Carl Eugen Hoyos wrote:
> > Reimar Döffinger <Reimar.Doeffinger <at> gmx.de> writes:
> > 
> > > Which of course is generally related to any kind of 
> > > "interlaced content" flag being really, really unreliable.
> > 
> > Which is why I am slightly against this patch:
> > Afaict, on DVB-T (SD), all material is signalled as being 
> > interlaced, although all movies and series are progressive 
> > (because 24Hz stretched and "interlaced" to 50Hz does not 
> > produce visible fields).
> > I suspect who works with interlaced material knows it 
> > and can set the scaling correctly.
> > 
> > Unrelated: Is a filter possible that detects by 
> > inspection if frames are interlaced?
> yes

I would suggest to detect if material is interlaced in a seperate
filter and set the flag correctly from there. And have scale use the
flag by default

we can have also 2 flags one indicating that the headers are signaling
the content as interlaced and another that marks the content as
interlaced by analyzing the bitmap

then again, if the header based flags are unreliable enough then
simply not passing them into the filter graph could be used to


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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